1. Field of the Invention
This invention relates to a tubing retrievable injection sleeve used in an oil/gas well for providing a controlled flow path for injection fluid into a selected portion of the formation surrounding a well and to apparatus and method for sequentially injecting fluid into a well. A variable orifice insert flow controller having a valve is used in conjunction with the sleeve to initially move a closure member of the sleeve to an open position by aligning ports in the sleeve and the housing of the tool while maintaining the valve closed thereby preventing injection fluid flow through the sleeve at a first pressure level.
Upon an increase in pressure the valve of the variable orifice insert flow controller will open thereby permitting full flow of fluid into the formation.
2. Description of Related Art
Currently injection sleeves for allowing fluid flow into a selected area of the formation surrounding an oil/gas well are actuated by dropping a ball of selected diameter to move a sleeve to open outlet ports.
This requires a ball dropping mechanism and is somewhat unreliable and results in the injection outlets to be in a permanently open position.
It is also known to use hydraulically actuated injection sleeves. However this technique requires extremely long control lines up to two miles in the case of a subsea system which is very costly, time consuming and may fail.